The invention relates to a process for producing a piezoelectric body which contains a ferroelectric material which may be polarized in an aligned, permanent fashion, and which also contains a bonding material.
In the production of piezoelectric ceramics by sintering appropriate starting materials, it is known to employ organic bonding agents in the dross. These bonding agents are converted into a volatile state during the sintering process and are no longer present in the finished material.
A French Pat. No. 2,005,462 (which corresponds to British Pat. Specifications 1,266,143; 1,266,144 and 1,266,145) discloses mixing powdery, ferroelectric material with a synthetic resin as bonding agent, and the manufacture of piezoelectric bodies therefrom. In this case, the bonding agent remains, as such, in the finished piezoelectric body.
It has been established that a mixed body composed of a ferroelectric material and a bonding material cannot be polarized in a satisfactory fashion and, in particular, cannot be polarized in a determinate fashion. The term "polarization" as used herein is to be understood as meaning the fundamentally unidirectional alignment of permanently existing polarizations of elementary domains of the ferroelectric material, as a result of the application of an electric voltage or the introduction of the material into an electric field.